Refactor: Centralize URL handling and add Bluesky integration

- Centralize urlopen functionality in utils.py with improved error handling
- Add configurable URL timeout across the project
- Introduce Bluesky client for fetching avatar from there (TBC)
- Support SSL verification bypass in debug mode

Signed-off-by: Oliver Falk <oliver@linux-kernel.at>

config.py

@@ -286,3 +286,5 @@ def map_legacy_config(trusted_url):
 
 # Backward compability for legacy behavior
 TRUSTED_DEFAULT_URLS = list(map(map_legacy_config, TRUSTED_DEFAULT_URLS))
+
+URL_TIMEOUT = 10